Rename HitTestResult to Hit

... and also move it to a new `text` module in `iced_core`

core/src/text.rs

@@ -0,0 +1,29 @@
+//! Draw and interact with text.
+use crate::Vector;
+
+/// The result of hit testing on text.
+#[derive(Debug, Clone, Copy, PartialEq)]
+pub enum Hit {
+    /// The point was within the bounds of the returned character index.
+    CharOffset(usize),
+    /// The provided point was not within the bounds of a glyph. The index
+    /// of the character with the closest centeroid position is returned,
+    /// as well as its delta.
+    NearestCharOffset(usize, Vector),
+}
+
+impl Hit {
+    /// Computes the cursor position corresponding to this [`HitTestResult`] .
+    pub fn cursor(&self) -> usize {
+        match self {
+            Self::CharOffset(i) => *i,
+            Self::NearestCharOffset(i, delta) => {
+                if delta.x > f32::EPSILON {
+                    i + 1
+                } else {
+                    *i
+                }
+            }
+        }
+    }
+}